What typically happens with severely B12-deficient babies:
The story begins with a vegan woman who gets pregnant and who does not take a vitamin B12 supplement. Over time, not consuming any vitamin B12 (or only tiny amounts of it) will lead to an increasingly severe B12 deficiency. This doesn’t always result in noticeable symptoms. If the vegan pregnant woman has a severe B12 deficiency, the vegan baby (foetus) will already have a very low B12 supply before birth. The baby will be born B12-deficient – again, possibly still without symptoms. (B12 deficiency can also result in miscarriages and stillbirth.)So, typically in these cases, the baby is born and the mother breastfeeds her baby exclusively, which is great theoretically, but her breastmilk is B12-deficient. Quickly, the baby will become more and more B12-deficient. Additionally, in many cases, the mother breastfeeds her baby exclusively (!) for longer (!) than six months (which is NOT recommended). Typically, the baby will then develop extremely severe B12 deficiency with serious harm to his/her health, usually at the age of 4 months or later. And these serious harmful effects typically are – quite many case reports have been published over the years – serious damage to his/her nervous system (i.e. brain shrinkage and other potentially irreversible nerve damage). Typical symptoms would be developmental delay, developmental regression (the baby cannot do anymore what he/she could do before, doesn’t smile anymore, etc.), irritability, hypotonia (“floppy baby”), weakness, fatigue, and failure to thrive. Epileptic seizures and other movement disorders are also possible symptoms. If treated quickly (with B12 injections by a medical doctor), this nerve damage can be reversible (i.e. it can be cured), but it is not sure if this damage can be reversed (cured) 100%. Typically, with treatment (B12 injections) the symptoms drastically improve quickly, often within only a few days! However ... worst case scenario: the baby is never treated and dies (worst case, but possible).
What happened in this particular case: a B12-deficient vegan baby from Trento (Italy, 2021):
The mother followed a completely vegan diet (no animal products), but it turns out that the mother also had an medical condition called “pernicious anaemia”. Pernicious anaemia means that there is a deficiency of “intrinsic factor”, which is a molecule we need to absorb vitamin B12 if the B12 is consumed in small amounts, i.e. from animal products (meat, fish, dairy), or B12-fortified foods, or low-dose supplements. If you take high-dose supplements (such as 2000 µg per week), the “intrinsic factor” is not very relevant.Anyway, the lead author of the study has kindly informed me [personal communication 2 Dec 2021; thank you!] that they think that the brain damage in the vegan baby boy (see below) was at least partly caused by the mother’s unsupplemented vegan diet (i.e. without any B12 supplement and probably no or very few B12-fortified foods). However, as the mother also had pernicious anaemia, I’m not entirely sure, that the vegan diet was THE main cause. Maybe any diet would have caused the same problem, because the woman couldn’t absorb B12 – this is not sure (maybe her absorption would have been good enough to at least absorb some B12 if she had consumed any B12). In any case, it is entirely certain that an unsupplemented vegan diet during pregnancy is extremely dangerous and will result in B12 deficiency and will likely result in serious harm (see below) for the baby. It is also very likely that the mother’s unsupplemented vegan diet (i.e. B12-free diet) made the situation (pernicious anaemia) much worse, even though this particular case was probably caused by the unsupplemented vegan diet AND the (diet-unrelated) pernicious anaemia.
So, here are the specifics of this unfortunate little vegan boy:
- The boy had been born at 37 weeks olds (three weeks early), with growth retardation (too small).
- The birthweight had been 2130 g (<3rd centile; i.e. the birth weight was quite low).
- At four months old, the paediatrician diagnosed the boy with failure to thrive (psychomotor regression and hypotonia). However, the vegan boy had normal strength and brisk reflexes, was able to follow objects visually, and smiled occasionally. No “babbling” was observed. The findings of the general physical examination were within the normal range without “dysmorphic features” (i.e. the baby boy’s body was normal, no physical malformations). “An observation was suggested”, meaning that the doctor didn’t treat the baby at this point, i.e. there was no B12 supplementation – because they didn’t know there was a B12 deficiency. The doctor/doctors didn’t know, at this point, that the mother and baby were vegan.
- He had been exclusively breastfed by his young vegan mother (mother’s exact age is not given).
- At six months old, the baby boy began to lose his appetite, started vomiting, and refused to be weaned (i.e. he did not want to eat complementary foods) [“his symptoms started at six months of age”].
- At nine month old, the baby boy was taken to the hospital (in Trento) with developmental regression.
- The boy had a severe B12 deficiency.
- At nine months, his weight was 5885 g (<3rd percentile; very low weight), he was pale, hypotonic, with no reaction to external stimuli (didn’t react to anything). Psychomotor regression was confirmed (i.e. mental and physical development was not healthy).
- At nine months the boy also had severe megaloblastic anaemia and the serum B12 level was so low it was undetectable. The plasma homocysteine levels (a functional marker of B12 deficiency) were very high, and urine methylmalonic acid (MMA; another functional marker of B12 deficiency) was also high.
- Serious harm caused: brain atrophy (documented on MRI scan pictures; see pictures below).
- The symptoms improved after vitamin B12 supplementation.
- Serious harm reversed: brain atrophy recovery (“brain grew back”) after B12 therapy.
- At nine months he also underwent a brain MRI scan which showed the brain atrophy [see pictures below]. The MRI scan shows a thinning of the “corpus callosum” (some part of the brain) and also of the optic nerves (nerve bundles leading to the eyes).
- The B12 deficiency was likely, at least partly, dietary (a vegan diet without a B12 supplement)´.
- Unlike the mother, the baby boy did NOT have “pernicious anaemia” (see below) or any disease (apart from the B12 deficiency).
In this picture you can see the brain shrinkage (= brain atrophy); top row: all the white areas in the top row which have disappeared in the bottom row indicate “a lack of brain”; top row: B12 deficiency state; bottom row: healthy state, after vitamin B12 treatment for 10 months; top row: if you look closely, in picture “b” you can see two small black arrows which point to the optic nerves (and these look a tiny bit thicker [healthy again] in picture “e” compared to picture “b” [B12-deficieny]).
Some specifics about the vegan mother:
- During pregnancy and breastfeeding she had no noticeable symptoms.
- But her blood tests showed that her B12 levels were so low that they were undetectable.
- However, the vegan mother also had “pernicious anaemia” (= intrinsic factor deficiency, unrelated to diet). The article states: “As the infant had been exclusively breastfed, his mother underwent […] tests. Although during pregnancy[,] labor and breast-feeding she did not present any particular symptoms or signs related to Vit-B12 deficiency, the exams revealed that her serum Vit-B12 level was also undetectable and her gastric APCA test [“anti-parietal cell antibody” level in the stomach] was consistent with pernicious anaemia. Moreover, it was only on this occasion that we discovered that she kept a strict vegan diet.”
- That means, only when the baby already had the brain damage (at nine months old), the doctors found out that the mother followed a vegan diet (without a B12 supplement). Had they known earlier, they would likely have tested for B12 deficiency earlier (during pregnancy) and avoided the tragedy.
Some quotes from the article:
“The relationship between Vit-B12 deficiency and neurological symptoms is poorly understood.”“As in our case, optic nerve thinning is another hallmark of the disease [B12 deficiency].”
“An early diagnosis and initiating administration [of B12 injections] are essential.”
“However, although Vit-B12 supplementation leads to a rapid clinical and morphological improvement, there are concerns regarding the long-term prognosis, as the child may be left with long-term intellectual problems.”
Reference:
Feraco et al. (2021): Clinical and Brain Imaging Findings in a Child with Vitamin B12 Deficiency; Pediatr Rep, 2021 Oct 25;13(4):583-588. doi: 10.3390/pediatric13040069 .
https://pubmed.ncbi.nlm.nih.gov/34842801/
https://pubmed.ncbi.nlm.nih.gov/34842801/